Cardiovascular disease: what is it and how do we prevent it?
During the 1940s, Sweden underwent major changes in lifestyle and social structure. These changes included automation of industry and transport, increased food production, changing food manufacturing and the creation of harmful ingredients such as trans fats, increased smoking and increased sedentary activity. This led to the emergence of risk factors such as high blood pressure, lipid disorder and diabetes. These risk factors lead to the accumulation of fat in the vessels of the heart (coronary arteries).
The accumulation of fat in the coronary arteries leads to the narrowing of the vessel, as a result of which it becomes more difficult for the blood to flow through the vessels. This gradually leads to oxygen starvation of the heart, which in turn leads to a pressing feeling of discomfort in the chest (so-called angina). In addition, fatty accumulations in the coronary arteries can become so inflamed that the vessel wall ruptures, forming a clot that further reduces blood flow in the vessel. Such a clot can even stop all flow in the vessel and this leads to a heart attack, as the oxygen deficiency in the heart muscle becomes too severe. Fortunately, most of the risk factors for heart attack and coronary heart disease can be detected and treated with simple methods. Research has shown that 90% of the risk of coronary heart disease can be modified with simple treatments and measures and therefore it is important to identify their risk of coronary heart disease and heart attack (1, 2).
The importance of risk factors for coronary heart disease
The main risk factors for coronary heart disease and heart attack are as follows:
- Smoking is associated with about 3 times increased risk of heart attack.
- Diabetes is associated with about 3 times increased risk of a heart attack. Read more about diabetes here.
- Blood lipid disorder is associated with about 4 times increased risk of heart attack.
- Hypertension (high blood pressure) is associated with about 3 times increased risk of heart attack.
- Abdominal obesity is associated with about 2.3 times increased risk of a heart attack. Read more about obesity and overweight here.
- Psychosocial stress is associated with about 2.5 times increased risk of heart attack.
- High intake of fruits and vegetables is associated with about 35% lower risk of heart attack.
- Exercise is associated with about 40% lower risk of heart attack.
- Moderate intake of alcohol is associated with approximately 20% lower risk of heart attack.
Knowledge of the significance of these risk factors for the development of coronary heart disease and heart attack came in the 1960s but it would be several decades before effective treatments were available. Despite this, the onset of heart attack began to decline already in the 1970s, which is likely to be an effect of folk formation. Extensive population campaigns where information on the risks of smoking, high blood pressure and lipid disorders is likely to have a major impact. In the 80s and 90s, effective treatments were introduced, and overall this has resulted in a half-fold heart disease in the last three decades. The incidence (number of patients) of a heart attack has thus halved in recent decades (3). Treatment of risk factors is considered to be the main explanation for this positive development (4).
Swedish National Board of Health and Welfare Report 2015
- In 2015, nearly 27,000 people had an acute myocardial infarction in Sweden
- 25 percent of all cases of acute myocardial infarction in 2015 led to death within 28 days.
- Men account for about 60 percent of all incidental cases of acute myocardial infarction.
Thus, science shows that coronary heart disease is caused by fat accumulation and inflammation of the heart vessels. This process begins in adolescence and it takes a couple of decades before the disease gives clinical symptoms (for example, angina pectoris). The cause of fat accumulation and inflammation is mainly the risk factors listed above. Detecting and treating these risk factors, as a rule, is simple, and the analyzes are available to everyone in the population. In addition to the above risk factors, genetics, socio-economic status (income, education, marital status, etc.) and environmental health factors (e.g. exhaust gases) also contribute. Science indicates that it is reasonable to consider its risk of coronary heart disease already at the age of 22 (5).
Below is a review of these risk factors.
1. Blood fats/lipids: cholesterol and triglycerides
♥ Feel free to read our article series about blood lipids, cholesterol and atherosclerosis.
Blood lipids are a collective name for fats in the blood. There are mainly two kinds of fat in the blood, cholesterol and triglycerides. Cholesterol is used to build cells and form hormones. Triglycerides are used as energy. Thus, high lipids in the blood can lead to the accumulation of fat in the vessels of the body, called varicose veins or atherosclerosis. It is easy to investigate if blood lipid levels are high and also it is easy to treat with blood-lowering treatment. Note that blood fat levels considered normal in Sweden exceed the levels required for a healthy life. There are data that suggest that lowering your blood lipids may be beneficial, regardless of the level of your lipids (6). However, you should not consume medicines unnecessarily; an individualised and careful review of risk factors is important to avoid using medicines unnecessarily. The better your health is (i.e. the better your risk factor profile is), the less benefit you will have from medicines that lower blood fats. We will discuss blood lipids, state treatment and others in future chapters.
Cholesterol occurs in the blood in the form of LDL cholesterol and HDL cholesterol. LDL cholesterol (often called bad cholesterol) transports cholesterol to the cells of the body. HDL cholesterol (often called the good cholesterol) removes cholesterol from the cells of the body. High levels of LDL cholesterol lead to increased atherosclerosis and, consequently, an increased risk of coronary heart disease, heart attack, stroke and peripheral vascular disease. There are some types of LDL cholesterol that are harmful and cause atherosclerosis. Unfortunately, Swedish health care does not measure the level of harmful LDL types, but instead measures the total amount of LDL in the blood (it is cheaper). The dangerous type of LDL cholesterol is the one called “small dense LDL”, precisely because it is small and has high density.
American and Swedish guidelines believe that LDL cholesterol should be measured and treated according to the LDL value. However, a wide range of studies suggest that LDL cholesterol is a clearly worse risk marker than the apocotoxic ratio. What is the Apoka quota? The apo ratio is the ratio of apolipoprotein B (Apo B) to apolipoprotein A1 (Apo A1). Apo B is harmful (it is actually a representative of small dense LDL) while Apo A1 is favorable. The quotient is obtained by dividing the amount of Apo B by Apo A1.
Generally, LDL cholesterol has nevertheless been used to make decisions about blood-fat lowering treatment. Guidelines suggest that all individuals with high LDL values should receive agressive diet and exercise therapy to lower their LDL cholesterol. Drug treatment with statins often becomes necessary to lower LDL cholesterol to the desired levels. For each unit (mmol/liter) lowering of LDL, the risk of severe cardiovascular disease (heart attack, stroke, etc.) is reduced by 22% and the risk of death is reduced by 10% (8). These figures come from a wide range of randomised controlled clinical trials.
High levels of HDL cholesterol are associated with a reduced risk of cardiovascular disease. However, it is not established whether HDL cholesterol itself is protective yet much speaks for it (7). It is believed that this is due to the fact that HDL removes cholesterol from the cells of the body and increases the breakdown of cholesterol. Despite this, several clinical studies, in which HDL cholesterol was raised with drugs, have failed to report a reduction in the risk of cardiovascular disease. Therefore, many today believe that HDL cholesterol is rather a marker: high levels HDL are a good signal, while low levels HDL signal that you are living less healthy.
Triglycerides are mainly derived from the diet. They are produced in the gastrointestinal tract and liver, and then used as a source of energy in the body. It is still unclear whether triglycerides can cause atherosclerosis. People with high levels of triglycerides usually have a higher risk of cardiovascular disease but it is not established that it is due to the triglycerides themselves or other factors related to high triglycerides levels. High triglycerides can be treated with fibrates but also with diet, exercise and weight loss. However, it has been shown that lowering triglycerides does not pose a reduced risk of cardiovascular disease. High levels of triglycerides are common in unhealthy diets, high alcohol consumption, Cushing’s disease, kidney disease, hypothyroidism, oestrogen therapy and cortisone treatment.
Who should examine their blood lipids?
There is scientific evidence to examine blood lipid from the age of 22 (5).
Symptoms of high blood lipids
High blood lipids usually do not give any symptoms. Some people get white-yellow deposits around the eyes, but most people with high blood lipids have no symptoms.
Should I eat statins if I have high blood lipids?
High blood lipids should be treated with statins if the benefits of treatment exceed the risks of treatment and if it is economically justifiable. This means that it is necessary to assess the overall risk factor profile and then decide whether drug treatment is necessary. If the risk of coronary heart disease is high, statins should be considered regardless of the effect of diet and exercise. High doses of statins protect better than low doses of statins, regardless of the effect on the LDL level. Statins do not increase the risk of cancer or death. It has been proved that statins can accelerate the development of diabetes in people who have precursors of diabetes. Statins are as effective in primary prevention (preventive purpose) as in secondary prevention (to prevent further cardiovascular events) (6). But, again, the effect is less the healthier you are.
What other medicines can be used for high blood lipids?
Resins, fibrates and cholesterol uptake inhibitors can also be used to lower cholesterol. For people with high levels of triglycerides, fibrates can be a better alternative than statins.
2. High blood pressure (hypertension)
♥ Learn more about hypertension and diabetes.
Blood pressure is the pressure in the vessels of the body and it is described by two values. The highest value — systolic pressure — is the maximum pressure in the vessels when the heart pumps. The lower value — diastolic pressure — indicates the pressure in the vessels between the heartbeats. A systolic pressure below 120 and a diastolic pressure below 80 is normal — it is usually written as “120/80”. Hypertension exists if the blood pressure is higher than normal. Hypertension, which occurs in 10 -25% of the adult population, is a risk factor for coronary heart disease, heart attack, stroke, kidney disease and peripheral vascular disease.
Why is it important to measure their blood pressure?
Hypertension is one of the absolutely most common and most important risk factors for cardiovascular disease. High blood pressure is the most common risk factor for heart attack, stroke, heart failure, atrial fibrillation and a number of other cardiovascular diseases. Hypertension is actually the most common cause of morbidity and mortality globally (9).
What symptoms give high blood pressure?
There are no symptoms of high blood pressure, unless complications have arisen. It is important to detect a high blood pressure in time to prevent the emergence of complications. People with hypertension are often other risk factors for cardiovascular disease. These include, for example, overweight/abdominal obesity, elevated blood lipids and diabetes.
Where does the limit of hypertension go?
- Optimal blood pressure: 120 systolic and 80 diastolic.
- Normal blood pressure: 120–129 systolic and 80–84 diastolic.
- High normal blood pressure: 130–139 systolic and 85–89 diastolic.
- Hypertension (abnormally high blood pressure) Grade 1: 140 – 159 systolic, 90–99 diastolic.
- Hypertension (abnormally high blood pressure) Grade 2: 160-179 systolic, 100-109 diastolic.
- Hypertensive crisis (requires emergency medical care): >180 systolic and > 110 diastolic.
Diagnosis of hypertension: hypertension
Blood pressure can vary greatly depending on what you do. When changing body position, straining or exercising, the blood pressure changes to adapt to the needs of the body. When properly conducted blood pressure measurement, blood pressure should be lower than 120 mm Hg systolic and lower than 80 mm Hg diastolic.
One has high blood pressure if systolic blood pressure is higher than 139 mm Hg or diastolic pressure is higher than 89 mm Hg. To be sure that you have high blood pressure, the pressure should be measured another 3 times within a month. If further measurements show that the pressure is 140/90 or higher, then most likely you have hypertension and then you should consult your doctor.
Systolic blood pressure is preferred as a risk factor
Diastolic blood pressure rises during the course of life until the age of 55, after which it gradually drops. Systolic blood pressure constantly rises throughout life. Therefore, elderly people may have a normal diastolic blood pressure but high systolic blood pressure. Therefore, systolic blood pressure is considered the most useful risk marker.
How to examine his blood pressure?
Blood pressure monitors can be found on the vast majority of medical institutions. Measuring blood pressure only takes a few minutes and there are even tonometers that you can have at home.
Who should examine their blood pressure?
Blood pressure can be examined starting from the age of 20 years. Even healthy individuals should be controlled their blood pressure because high blood pressure is very common and usually does not cause any symptoms.
What to consider when measuring blood pressure
You should refrain from caffeine and smoking as well as snuff no later than 30 minutes before measuring your blood pressure. You shall sit in a comfortable chair with your arms hanging down. After 5 minutes of rest in the chair, the pressure can be measured. The blood pressure cuff should be placed at the level of the heart (i.e. at chest level). A blood pressure is calculated as the average of two measurements made every 1 minutes.
How can I lower my blood pressure?
Healthier diet, increased exercise, better lifestyles and weight loss are the cornerstones of the treatment of hypertension. Even minor reductions in blood pressure (reduction of 3-5 mm Hg) result in significant health benefits through a reduced risk of cardiovascular disease. Drug treatment can be recommended to everyone with hypertension, unless lifestyle changes lead to normalized blood pressure.
Increased physical activity: exercise 30 min 3-7 times per week can lower blood pressure by the order of 4 mm Hg systolic and 3 mm Hg diastolic. Exercise also has other beneficial effects for health.
Weight loss (if overweight): Weight loss 3 -9% is able to lower blood pressure about 3 mm Hg systolic and 3 mm Hg diastolic and also has a very good influence on other risk factors such as blood lipids and sugar.
Diet: There are studies that suggest that increased amounts of fruits, vegetables and low-fat products can lower blood pressure in the same order of magnitude as exercise. People who consume a lot of salt should reduce their salt intake as this can have a significant effect on blood pressure.
Reduction of alcohol consumption: Reducing alcohol intake among high consumers is associated with a dose-dependent reduction in blood pressure.
Stress management: High stress level is likely to lead to higher blood pressure.
What to consider when measuring blood pressure
- The wide blood pressure cuff must be adjusted to the arm circumference of the person. Too small cuff can give a false high value and too large cuff can give too low value.
- Equipment should be calibrated annually and checked for hoses, fittings and valves.
- The cuff must be at heart height. The arm must be at heart height. Too low level of the arm can result in too high pressure.
- Irregular heart rhythm makes it more difficult to measure the pressure because the pulse varies from stroke to blow.
- The arm must be completely relaxed and the person must sit in a resting position. A tense arm muscle gives false high value.
- Many especially elderly patients and many years of diabetes have stiff blood vessels (so-called Mönkeberg sclerosis), which causes false high blood pressure and can cause very different blood pressure in their arms.
- If the person is stressed, has pain, freezes, freshly smoked or drunk coffee, this a false high value.
- Blood pressure should not be taken in conjunction with blood sampling (tends to give high value due to stress).
- Some people get false high values if they visit a medical institution and more often pressure when the doctor takes it than when a nurse does it (white coat hypertension).
Automal/electronic meters are of varying quality and place great demands on technology. They also give incorrect values if blood pressure is very low, very high, if the pulse is low or high and in case of irregular heart rhythm. Only manual values should serve as a basis for decisions on treatment.
3. Diabetes: high blood sugar (glucose)
♥ Please read our introduction to type 2 diabetes or type 1 diabetes.
Diabetes is a collective name for several diseases characterized by elevated blood sugar. Type 1 and type 2 diabetes are the most common forms. Among women, gestational diabetes also occurs. Type 2 diabetes affects adults and the elderly (usually obese individuals), whereas type 1 diabetes most often affects children and adolescents.
Type 1 and type 2 diabetes constitute strong risk factors for cardiovascular disease. Type 1 diabetes causes high blood sugar while type 2 diabetes is usually accompanied by a number of other physiological disorders, such as high blood pressure and high blood lipids. Overweight and obesity (especially abdominal obesity) explain a large proportion of the disorders in type 2 diabetes.
It has been shown that precursors of diabetes also entail an increased risk of cardiovascular disease. In addition, there is scientific support that even minor increases in blood sugar cause an increased risk of cardiovascular disease, even in people who do not have diabetes.
Symptoms of diabetes
Type 2 diabetes, and especially the precursors of the disease, do not have to bring any symptoms. Those who have symptoms are often bothered by fatigue, weakness, thirst, they urinate more often and in large quantities. Vision may be blurred and itching may occur in the lower abdomen. Here you can read more about symptoms of type 1 and type 2 diabetes:
- Symptoms of Type 1 Diabetes
- Symptoms of Type 2 Diabetes
Variants of blood sugar
A blood sugar higher than normal speaks for diabetes or precursors of diabetes (so-called pre-diabetes). Blood sugar can be measured at any time of day (“random value”) but it is beneficial to take a value after fasting (“fasting”). Nowadays, HbA1c can also be used to examine blood sugar. HbA1c — often referred to as ‘long-term sugar’ — testifies to the average blood sugar level over the last 2 months. Random, fasting and HbA1c can all be used to investigate if you have diabetes. In Swedish healthcare, faste-value and HbA1c are preferred.
4. Abdominal obesity, obesity and overweight
♥ Feel free to read our introduction to overweight and obesity and how overweight and obesity cause diabetes and other diseases.
Overweight and obesity are a huge social problem in Sweden as well. The vast majority of people with overweight or obesity have some degree of abdominal obesity, which means that you have a lot of fat in the stomach. Abdominal obesity is considered particularly harmful because the fat in the abdomen has a particularly large (negative) impact on the body’s metabolism. People with abdominal obesity have a significantly increased risk of type 2 diabetes, high blood pressure and high blood lipids. Abdominal obesity also increases the risk of heart attack, stroke, heart failure and some cancers.
- Yusuf, S., Hawken, S., Ounpuu, S., Dans, T., Avezum, A., Lanas, F., et al. (2004). Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet, 364(9438), 937–952.
- Yusuf, S., Rangarajan, S., Teo, K., Islam, S., Li, W., Liu, L., et al. (2014). Cardiovascular risk and events in 17 low-, middle-, and high-income countries. N Engl J Med, 371(9), 818–827.
- Nabel, E. G., & Braunwald, E. (2012). A tale of coronary artery disease and myocardial infarction. N Engl J Med, 366(1), 54–63.
- Ford, E. S., Ajani, U. A., Croft, J. B., Critchley, J. A., Labarthe, D. R., Kottke, T. E., et al. (2007). Explaining the decrease in U.S. deaths from coronary disease, 1980-2000. N Engl J Med, 356(23), 2388–2398.
- Keaney, J. F., Curfman, G. D., & Jarcho, J. A. (2014). A pragmatic view of the new cholesterol treatment guidelines. N Engl J Med, 370(3), 275–278.
- Collins, R., Reith, C., Emberson, J., Armitage, J., Baigent, C., Blackwell, L., et al. (2016). Interpretation of the evidence for the efficacy and safety of statin therapy. Lancet, 388(10059), 2532–2561.
- Khera, A. V., Demler, O., Adelman, S. J., Collins, H. L., Glynn, R. J., Ridker, P. M., et al. (2017). Cholesterol Efflux Capacity, HDL Particle Number, and Incident Cardiovascular Events. An Analysis from the JUPITER Trial (Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin). Circulation
- Cholesterol Treatment Trialists’ (CTT) Collaboration, Baigent, C., Blackwell, L., Emberson, J., Holland, L. E., Reith, C., et al. (2010). Efficacy and safety of more intensive lowering of LDL cholesterol: a meta-analysis of data from 170,000 participants in 26 randomised trials. Lancet, 376(9753), 1670–1681.
- Ezzati, M., & Riboli, E. (2013). Behavioral and dietary risk factors for noncommunicable diseases. N Engl J Med, 369(10), 954–964.